Rewrite the fractions so they have a common denominator:
7/50 = 14/100
Now you have:
245 14/100 - 128 53/100
Make the first fraction larger than the second one, by subtracting 1 from the whole number and adding 100/100 to the fraction to get
244 114/100
Now subtract:
244 114/100 - 128 53/100
244 - 128 = 116
114/100 - 53/100 = 61/100
The answer is 116 61/100 more miles.